Automatic feed for sharpening apparatus



March 27, 1956 F. M. YAGLE AUTOMATIC FEED FOR SHARPENING APPARATUS 2 Sheets-Sheet 1 Filed July 20, 1954 INVEN TOR. F/PZD M V4 61 E March 27, 1956 F. M. YAGLE AUTOMATIC FEED FOR SHARPENING APPARATUS 2 Sheets-Sheet 2 Filed July 20, 1954 EEE AUTOMATIC FEED FUR SHENING APPARATUS Fred M. Yagle, Philadelphia, Pa.

Application July 29, 1954, Serial No. 444,599

7 Claims. (Cl. 51-466) This invention relates to sharpening apparatus, and particularly to an automatic feed mechanism for a motordriven grinding wheel as is commonly employed in the shaipenin of lawn mower blades.

in the sharpening of lawn mower blades, it is necessary that the bevel or angle at which the blades are sharpened be constant from blade to blade, for maximum efiectiveness in cutting. In some of the sharpeners presently on the market, particularly those in the nature of a grinding wheel, the wheel is set at the angle of cut desired, relative to the position of the blade being sharpened, and then is manually moved toward and away from the work as the need arises. it is obvious that each time the grinding wheel is moved, the original angular setting is disturbed, with the result that a ditierent bevel is likely to exist on the various blades of the lawn mower.

With this in mind, it is an object of the present invention to provide an automatic feed for a sharpening apparatus generally taking the form of a motor-driven grinding Wheel.

it is another object of this invention to provide an automatic feed for a grinding wheel apparatus, which feed is adapted for maintaining a fixed angular setting of the grinding wheel relative to the work so that a lawn mower can be uniformly sharpened.

It is a further object of the invention to provide an automatic feed for a grinding wheel apparatus which is relatively simple in construction, convenient and accurate.

These objects, together with other objectives and advantages to be derived from the present invention, will become apparent from a reference to the following detailed description and accompanying drawings wherein similar numerals refer to similar parts throughout the several views.

Figure l is a side elevational view of a sharpening apparatus in the nature of grinding wheel showing the feed mechanism of the present invention in association therewith.

Figure 2 is a sectional view of the feed mechanism taken along the line 2-2 of Fig. 1, with parts broken away, and showing in bottom plan view the general arrangement of the various parts of the mechanism.

Figure 3 is a sectional View of a portion of the sharpening apparatus with parts broken away, taken along the line 33 of Fig. 1, and showing a portion of the feed mechanism in front elevation.

Figure 4 is a sectional view of a portion of the feed mechanism taken along the line 4-4- of Fig. 1.

Figure 5 is a sectional view of part of the feed mechanism, with parts broken away, taken along the line 55 of Fig. 2, illustrating the piston-like feature of adjusting mechanism.

Figure 6 is a sectional view of a portion of the feed mechanism illustrating the details of the feeder screw, taken along the line 66 of Fig. 4.

Referring to the drawings, and particularly Fig. 1 thereof, a grinding wheel as is commonly used in the sharpening of lawn mower blades and the like is referred 2,739,428 Patented Mar. 27, 1956 to by the numeral 14). This grinding wheel 10 is driven by means of an electric motor 11 through a motor belt 12 operatively joining the motor to the grinding wheel. The motor 11 is mounted on a support plate 13 which also carries a dust shield 14 in a position immediately behind the grinding wheel 10. Fixidly attached to the upper surface of the support plate 13 is a tapped tubular member 15 which is adapted to receive a threaded elevating rod 16 having a handle 17 attached thereto. The free end of the rod 16 slidably resides in a longitudinal groove 13 provided therefor in a complementary base plate 19 lying beneath the support plate 13 and in spaced relationship therewith.

Fixedly attached to the underside of the support plate 13, as shown in Figs. 13, are a pair of spaced cylinders iii and 21, which cylinders are joined by means of a crossbar 22 welded thereto. The said cylinders 20 and 21 are attached to the support plate 13 by means of bolts 23 and 24 which are integrally connected thereto, and which pass upwardly through the plate 13 in apertures provided therefor and receive nuts 25 and 26. Residing within the cylinders 26) and 21 in telescoping relationship therewith are a pair of plungers 2'7 and 28. The plungers 27 and 23 are pivotally attached to a bracket 2& carried by the base plate 19 at the end thereof remote from the groove 18, and attached thereto by means of screws 30 and 31 as shown in Fig. 4. It will be noted that the ends of the plungers attached to said bracket 29 are substantially square in cross-section and reside in square cut-outs provided therefor. As shown in Fig. 5, the ends of the plunger-s are slightly rounded as at 3t to facilitate angular movement of the said plungers relative to the bracket 29. Looking at Figs. 2 and 4, it will be seen that pivot rods 31 and 32 are provided in each side of the bracket 29 for accommodating the pivotal movement of the plungers 2'7 and 23, which pivot rods are precluded from sidewise movement by means of set-screws 33 and 34.

In order to control the feeding of the grinding wheel 10 toward and away from the work at a given angular setting, the bracket 29 pivotally carries a worm block 35 between the plungers 27 and 28, as shown in Figs. 2 and 4, the said block being pivotally mounted on the ends of the pivot rods 31 and 32 in a recess provided therefor in the bracket 29 and having a rounded bottom as shown in Fig. 6 to facilitate its pivotal movement in said bracket. Passing through the worm block 35 and supported thereby is a threaded rod 36 having a handle extension 37 thereon with a knurled knob 38 integrally attached thereto. The threaded rod 36 is precluded from axial movement within the worm block 35 by mean of stop nuts 39 and it? residing on said rod in abutting relationship with both sides of the said block, as shown in Figs. 2 and 6. The free end of the threaded rod 36 is threadaoly received in a nut 41 integrally attached to the cross-bar 22 in axial alignment with an aperture provided therein to accommodate the axial movement of the said rod through said nut and crossbar. it will thus be noted that with the cylinders 2d and 21 and the cross-bar 22 occupying a fixed position relative to the support plate 13, and with the bracket 29 being fixedly attached to the base plate 19, the turning of the knurled knot 33'causes the entire support plate 13, and the cylinders 24 and 21 attached thereto, to move inwardly or outwardly with respect to the bracket 29, by virtue of the threaded relationship between the rod 36 and the nut 41 on the cross-bar 22., the said cylinders sliding upon the plungers 27 and 28 in a well-known telescoping manner for this purpose. By this means, the grinding wheel is moved toward or away from the work without disturbing the angular setting of said wheel with respect to the item being sharpened.

3 Operation While the operation of the present invention should be obvious after the above description thereof taken in conjunction with the accompanying drawings, a brief summary of its operation will be given here for purposes of clarity and completeness.

For the purpose of sharpening the lawn mower blades, the sharpening apparatus and lawn mower are first both mounted on a common supporting bed, which bed does not constitute a part of the present invention. The lawn mower is maintained in a fixed position thereon, while the shaipening apparatus is adapted to be movable transversely thereof, as on runners or the like. Thus, to sharpen a blade of the lawn mower, the support plate 13 for the grinding Wheel and motor is first moved away from the mower blades by turning the knurled knob 38 of the feed mechanism. The desired angular setting of the grinding wheel with respect to the mower blades is then obtained by raising or lowering the support plate 13 by turning the handle 17 which controls the elevating rod 16. Having thus established the desired angular setting for the grinding wheel, the wheel is moved inwardly toward the mower blades by again turning the knurled lmob 38 until the wheel contacts the blade to be sharpened. The entire blade may then be sharpened by moving the sharpening apparatus transversely thereof on the supporting bed referred to above.

It is seen from the above description of the present invention, that a novel feed mechanism is provided for use with a sharpening apparatus in the nature of a grinding wheel, which permits the operator to move the grinding wheel away from the item being worked upon, without changing the angular setting or bevel of the wheel with respect thereto. Thus, as applied to a grinding wheel for use in sharpening the blades of a lawn mower, it is possible, through the use of this feed mechanism, to provide the blades with a uniform cutting edge.

It will also be noted that this feed mechanism may readily be attached to already existing motor-driven grinding wheel assemblies with but little modification thereto for this purpose, due to the relatively simple construction of this mechanism.

Although the present discussion of this invention has been limited to the above-described preferred embodiment, variations thereof are possible without departing from the spirit of the invention. It is to be understood, therefore, that the invention is not to be limited to the particular embodiment disclosed, but only to the inventive concept as defined by the appended claims.

What is claimed is:

1. A feed mechanism for use with a grinding wheel sharpening apparatus having a movable wheel support plate and a fixed base plate in angular relation to said support, the said mechanism comprising, a plunger pivotally attached to said fixed plate, a complementary cylinder attached to said support plate and receiving said plunger, means for causing angular adjustment of said support towards and away from said base plate, and means for causing telescoping of said cylinder relative to said plunger so as to move the grinding wheel toward and away from work being sharpened.

2. A feed mechanism for use with a grinding wheel sharpening apparatus having a movable wheel support plate and a fixed base plate with the support plate angularly adjustable towards and away from said base plate, the said mechanism comprising, a plunger pivotally attached to said fixed plate, a complementary cylinder fixedly attached to said support plate and adapted to receive said plunger, and manually controllable means for causing telescoping of said cylinder relative to said plunger so as to move the grinding wheel toward and away from work being sharpened.

3. A feed mechanism for use with a grinding wheel sharpening apparatus having a movable wheel support plate and a fixed base plate with the support plate angularly adjustable relative to said base plate on an axis substantially parallel to said plates, the said mechanism comprising, a plunger pivotally attached to said fixed plate, a complementary cylinder fixedly attached to said support plate and adapted to receive said plunger, and screw control means attached to said fixed plate and support plate for causing telescoping of said cylinder relative to said plunger so as to move the grinding wheel toward and away from work being sharpened.

4. A feed mechanism for use with a grinding wheel sharpening apparatus having a movable wheel support plate and a fixed base plate with the support plate angular-1y adjustable to and from said base plate, the said mechanism comprising, a plunger pivotally attached to said fixed plate, a complementary cylinder fixedly attached to said support plate and adapted to receive said plunger, and manually operable screw control means pivotally attached to said fixed plate for causing telescoping of said cylinder relative 'to said plunger so as to move the grinding wheel toward and away from work being sharpened.

5. A feed mechanism for use with a grinding Wheel sharpening apparatus having a movable wheel support plate and a fixed base plate with the support plate angularly adjustable relative to said base plate on an axis substantially parallel to said plates, the said mechanism comprising, a pair of spacedparallel plungers pivotally attached to said fixed plate, a pair of complementary cylinders attached to said support plate and aligned for receiving said plungers in telescoping fashion, and feed control means for causing telescoping of said cylinders relative to said plungers so as to move the grinding wheel toward and away from work being sharpened.

6. A feed mechanism for use with a grinding wheel sharpening apparatus having a movable wheel support plate and a fixed base plate, the said mechanism comprising, a pair of spaced plungers pivotally attached to said fixed plate, a pair of spaced complementary cylinders fixedly attached to said support plate and aligned for receiving said plungers in telescoping fashion, a cross-bar joined to the said spaced cylinders and lying therebetween, the said cross-bar having a tapped bore therein, and a threaded rod attached to said fixed plate and received in said tapped bore for causing telescoping of said cylinders relative to said plungers so as to move the grinding wheel toward and away from work being sharpened.

7. A feed mechanism for use with a grinding wheel sharpening apparatus having a movable wheel support plate and a fixed base plate, the said mechanism comprising, a bracket attached to said fixed plate, a pair of spaced plungers pivotally attached to said bracket, a pair of spaced complementary cylinders fixedly attached to said support plate and aligned for receiving said plungers in telescoping fashion, a cross-bar joined to the said spaced cylinders and lying therebetween, the said cross-bar having a tapped bore therein, a screw-supporting member pivotally mounted in said bracket intermediate said plungers, a screw carried by said screw-supporting member having one end threadably received in said tapped bore, and a knurled knob on the other end of said screw, the turning of said screw in said bore causing telescoping of said cylinders relative to said plungers so as to move the grinding wheel toward and away from work being sharpened.

References Cited in the file of this patent UNITED STATES PATENTS 799,700 Youngstrom Sept. 19, 1905 1,344,168 Brown June 22, 1920 1,955,636 Kistner Apr. 17, 1934 1,958,734 Woodsmall May 15, 1934 2,012,065 Haas et a1 Aug. 20, 1935 2,187,289 Utterback Jan. 16, 1940 2,476,741 Landis July 19, 1949 2,655,768 Bartell Oct. 20, 1953 

